GuixSD + GNOME + Wacom Tablet = No tablet detected?

From:

Chris Marusich

Subject:

GuixSD + GNOME + Wacom Tablet = No tablet detected?

Date:

Sat, 02 Apr 2016 21:15:39 -0700

User-agent:

Gnus/5.13 (Gnus v5.13) Emacs/24.5 (gnu/linux)

Hi,
I'm using GuixSD v0.10.0 with GNOME. I have a Wacom tablet. When I
plug it in, activity in dmesg suggests the tablet is successfully
discovered, and I can move the mouse and click using the stylus, which
is nice, but it's jittery and I can't configure it. When I click on
"Wacom Tablet" in the GNOME settings, I get the following error:
No tablet detected
Please plug in or turn on your Wacom tablet
I thought maybe the problem was that I was missing necessary packages.
However, the "gnome" package is installed globally, and I see that its
dependencies include both libwacom and xf86-input-wacom. Just to be
extra certain, I tried installing those two packages in my user profile,
and rebooted, but the result remained the same.
Is there something else I have to do to enable "Wacom Tablet" in the
GNOME settings? I feel like I'm missing something simple.
--
Chris